Sensor units capable of being mounted to a measurement object to be monitored such as, for instance a rotor blade of a wind turbine, are in general built as patches including relevant sensor elements for detecting the measurement parameter of interest. In this context, fiber optic sensors play an important role, since these, due to the optical transmission of measurement signals via a light guide, are substantially insusceptible to external influences such as electromagnetic fields and provide for a fast data transmission. Furthermore, fiber optic sensors exhibit good electromagnetic compatibility (EMC), In fiber optic sensors, the measurement signal derived from the measurement parameter is optically transmitted by means of a light guide. Fiber optic sensors may in this case be designed as extrinsic sensors in which the light guide merely serves to transport the optical radiation. The design of fiber optic sensors as intrinsic sensors is further widely spread, in which the sensor element such as a fiber Bragg grating (FBG), for example, is contained in the sensor fiber itself.
An intrinsic fiber optic sensor is sensitive to mechanical structural changes such as, for instance elongation and/or compression, as well as to temperature variations. For measuring a parameter to be detected, the sensor unit or the fiber optic sensor element is appropriately connected to the measurement object, wherein undesired influences need to be compensated and measuring sensitivities be set. It is therefore desirable to further improve sensor patches having fiber optic sensors.